Distributor actuator unit with solenoid advance

ABSTRACT

A combination vacuum and solenoid operated actuator unit attachable to an ignition distributor of an emissions controlled internal combustion engine and enabling selective independent spark advance adjustment of the engine timing mechanism between positively established differential stop positions from an initial setting for reduced emissions at engine idling conditions. The solenoid is of the continuous duty variety energized through the vehicle ignition switch during starting operation of the engine and serves to provide a predetermined amount of spark advance during cranking of the engine to improve startability, especially with lean fuel air mixtures.

United States Patent Carter et al.

I 1 DIS'IRIBU'IOR ACTUATOR UNI'I WITH SOLENOID ADVANCE [75] Inventors: Ivor W. Carter, Detroit; Ian J. C.

Scott, Madison Heights, both of Mich.

[73] Assignee: Chrysler Corporation, Highland Park, Mich.

[22] Filed: Aug. 4, 1971 [21] Appl. No.: 168,880

[52] US. Cl 123/117 A [51] Int. Cl. F02p 5/04 [58] Field of Search 123/117 A [56] References Cited UNITED STATES PATENTS 3,301,242 1/1967 Candelise 123/117 A 3,452,728 7/1969 Salomon 123/117 A 3,561,410 2/1971 Soeters l23/117A 3,603,298 9/1971 Toda 123/117 A [451 Jan. 29, 1974 3,272,191 H1966 Walker 123/117 A 1,785,902 12/1930 Hardman i 1. 123/1 [7 A 3,630,181 12/1971 Orlich 123/117 A Primary ExaminerLaurence M. Goodridge Assistant ExaminerCort R. Flint 57 ABSTRACT A combination vacuum and solenoid operated actuator unit attachable to an ignition distributor of an emissions controlled internal combustion engine and enabling selective independent spark advance adjustment of the engine timing mechanism between positively established differential stop positions from an initial setting for reduced emissions at engine idling conditions. The solenoid is of the continuous duty variety energized through the vehicle ignition switch during starting operation of the engine and serves to provide a predetermined amount of spark advance during cranking of the engine to improve startability, especially with lean fuel air mixtures.

12 Claims, 17 Drawing Figures PATENTED 3.788290 SHEET 1 BF 5 V I ENTORS. 1335 477 .774, 560/? My M014 PATENTEB JAN 2 9 2974 SHEET 2 OF 5 wr M if; fl ru h EM; 1 F/ /r 1 w M 4 A z z Z M /fi y W E 77% W W W id 7 W Ma wWQ Q J 7 L7% INVENTORJ. J 1/07 1 7 1 DISTRIBUTOR ACTUATOR UNIT WITH SOLENOID ADVANCE BACKGROUND AND SUMMARY This invention relates to engine ignition timing control devices and, more particularly, to an improved spark advance actuator unit for the ignition distributor of an emissions controlled internal combustion engine.

Requirements for reduction of vehicle exhaust emissions have necessitated the use .of lean fuel air mixtures and the retardation of engine timing at engine idle conditions. While the engine ignition distributor equipped with a conventional vacuum operated spark advance control unit can be set in an initial position to retard engine timing for decreasing exhaust emissions at engine idle conditions, this setting is too far retarded for satisfactory engine starting purposes with emissions controlled engines. Such engines employ lean fuel air mixtures which require a considerably advanced spark setting for ease of startability and to avoid objectionable backfiring. Because of the low cranking speed and the absence of any engine vacuum at starting, the conventional automotive distributor equipped with engine governor and vacuum operated spark advance structures is incapable of providing both spark advance at start and retarded spark at idle.

Accordingly, the present invention seeks to provide an improved spark advance actuator control unit for an ignition distributor of an emissions controlled engine that avoids the above objections. Specifically the invention seeks to provide an ignition distributor spark advance control unit, which provides both a predetermined amount of spark advance for engine starting purposes and a less advanced or retarded spark setting at engine idle for emissions reduction purposes without interference with the normal vacuum modulation of the spark advance control during off-idle running conditions.

Toward accomplishment of the foregoing, the invention provides a combined vacuum-solenoid operated actuator unit structure for an ignition distributor of which the solenoid section is energized from the vehicle storage battery through the ignition switch to provide a predetermined amount of spark advance during engine starting. The solenoid is de-energized when the ignition switch is in any of its other positions, including its run position, where the actuator control unit is in its initial position corresponding to the spark retarded setting of the distributor for reduction of emissions at engine idle conditions. During off-idle run conditions, normal vacuum modulation is available through the vacuum section of the actuator unit to advance the engine timing over a continuous range of spark settings between predetermined stop limits which include a positively established stop position for the solenoid actuator unit intermediate the positive stop positions of the vacuum actuator section.

The structure and operation of the invention together with the advantages thereof will be understood from the detailed description of the preferred embodiment of the invention made with reference to the accompanying drawings.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation sectional view of the actuator unit and associated distributor showing the parts of the actuator unit in one of the operated positions thereof;

FIG. 2 is an enlarged sectional top plan view taken in the direction 22 of FIG. 1 and shows the parts of the DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1 of the drawings, the actuator control unit C is shown in conjunction with an ignition distributor mechanism D for producing and controlling the ignition and ignition timing of an internal combustion engine. The distributor, which is of conventional design related to that shown and described in U.S. Pat. No. 2,688,058, includes a cylindrical housing 10 having a detachable distributor cap 12 at its upper end and an integrally formed, downwardly extending tubular shank 15 with a stepped mounting flange 22 near its lower end by which it is secured to an opening in the engine block (not shown). Shank 15 includes a pair of axially spaced sleeve bearings 17 therein surrounding the distributor rotor shaft 18, which is suitably coupled at its lower end to be rotatably driven by the engine cam shaft (not shown).

In the housing is a centrally apertured stationary base plate 21, and below this plate is located the conventional centrifugally operated governor mechanism 25, which is driven from the rotor shaft 18. The weights of the governor mechanism are coupled through pins 26 and slotted plate 28 to the lower end of an adjustable sleeve 29, which is carried on the rotor shaft 18 to adjust the angular position of the sleeve 29 relative to the rotor shaft in a spark advance direction with increasing engine speed. At its upper end sleeve 29 carries the rotor cam 30, which is located above the base plate 21. Sleeve 29 extends through the base plate 21 and through a centrally apertured breaker or timing plate 50, which is supported on the base plate as shown in the above patent and is adjustable in a spark advance direction by the subject actuator unit for limited arcuate movement relative to the base plate and rotor cam. Plate carries a breaker contact assembly, which may be of the type shown in the above patent and is operated from the lobes formed on the hexagonally or octagonally shaped rotor cam 30 for periodically interrupting the energization of the ignition coil of the vehicle engine ignition circuit.

The actuator with which the present invention is concerned includes a vacuum section v and a solenoid section s, which are independently selectively operable to change the position of the breaker plate 50, and therefore the breaker contact assembly carried thereon, relative to the distributor rotor cam. Positioning of the breaker plate is effected from control link element 102, which forms a part of a yieldable or telescoping thrust rod assembly 101 operated by the actuator unit. Control link 102 is pivotally coupled at one end off centrally of or eccentrically to the breaker plate 50 and passes through a window opening 103 in the distributor housing and into the actuator unit where it is coupled to the actuator unit for selective independent Iongitudinal movement by the solenoid section and the vacuum section thereof.

The actuator unit C is contained within a two-piece, thin wall housing 90, which is formed of magnetically permeable material and includes a bell-shaped forward member 91 and a cup-shaped rear member 92, respectively containing the vacuum section v and the solenoid section s of the actuator unit. Forward housing member 91 includes a generally hexagonal cup-shaped end portion 118, which has an integrally formed and centrally located tubular spout or conduit 1 19 extending axially outwardly thereof, and a conically shaped, rearwardly extending body portion 20, which has a radially outwardly extending flange 121 formed thereon. Rear housing member 92 includes a cup-shaped portion 110 which has a centrally apertured end wall 111 adjacent the distributor, and a diametrically enlarged, integrally formed cylindrical portion 113 adjacent the bellshaped housing member 91. The housing members 91 and 92 .are assembled together after the various elements and sub-assemblies of the actuator unit have been positioned in the respective housing portions as described in connection with FIGS. 4-17.

Starting first with the rear housing member 92, this portion of the actuator unit receives the solenoid section; a stop plate, bushing and diaphragm subvassembly; and the aforementioned control link 102 in the order described.

As best shown in FIG. 2, the solenoid section includes a field coil 124; a stationary face plate 132, a two-piece core structure including a tubular core ring member 136 and an axially rearwardly spaced and elongated tubular core sleeve member 142; and a movable armature assembly 150 intermediate the core ring 136 and the core sleeve member 142.

As shown in FIGS. 4 and 5, the rearwardly located tubular core member 142 has a reduced end portion 143 on which is received a centrally apertured and sector-shaped retainer plate 162, which is recieved in and positioned adjacent the end wall 111 of the rear housing member 92. The reduced end of the core member passes through centrally located aligned apertures, which are provided in the retainer plate 162, the end wall 111 of the housing member 92 and in a bracket mounting member 93 to which the core member is staked with the aforementioned parts thereon as shown. Bracket mounting member 93 is spot welded to the exterior surface of the housing end wall 111 and is releasably fastened by screws 94 for subsequent attachment to the distributor housing 10. V I l Solenoid coil 124 comprises approximately 800 turns of number 22 AWG copper wire wound on a spool shaped insulating bobbin 127, which is received within the housing member 92 on the stationary tubular core portion 142 as shown in FIGS. 6 and 8 where it is positioned against a pair of resilient tabs 164,164 struck from one side of the retainer plate 162. One end of the solenoid coil winding is connected to a terminal tab portion 165, which is struck from the opposite side of the retainer plate 162 and extends through a pair of aligned openings 166 in the rear housing end wall 111 and in the bracket 93. The other end of the solenoid coil winding is connected to an electrical pigtail 128 extending outwardly of the housing through an insulating grommet 129 contained in another aperture 116 of the housing end wall.

As shown in FIGS. 7 and 9, face plate 132 is a thin circular disk, which is received on and secured, as by spinning, to the reduced outer or forwardly located end of the core ring 136 and has a diametrically spaced pair of peripherally disposed, U-shaped notches 134,134 formed therein. The notches extend through the plate and are in registering communication with a pair of aligned apertures 115,115 in the circular land portion 114 formed between the cylindrical portion 113 and the cup-shaped portion of the rear housing member 92.

As shown in FIG. 7, the enlarged inner or rearwardly located end of the core ring 136 has a radially inwardly extending stop flange 138 thereon, which cooperates with a radially outwardly extending flange 153 formed on the forwardly located end of a tubular brass sleeve member 152 inserted from its reduced end into the core ring. Sleeve member 152 constitutes a part of the armature assembly 150, which is movable relative to the face plate 132 and core ring 136, and carries the armature element 156, which is recieved on and positioned against a shoulder 154 formed on the slightly reduced end of the sleeve carrier 152 after the latter has been inserted into the core ring 136. As shown in FIG. 7, armature element 156 has a radially outwardly extending, forwardly located flanged end 158 and a generally spherically shaped, rearwardly located end. 160, which is staked to the carrier sleeve 152 and forms a self-aligning bearing with the rearwardly disposed core member 142 in which it is subsequently received.

The face plate 132, core ring 136, armature carrier 152 and armature element 156 are assembled in the order described to form the sub-assembly shown in FIG. 7 in which the distance A between the rearwardly disposed face of the core ring 136 and the forwardly disposed face of the armature element 156 constitutes the working air gap of the solenoid armature assembly. The sub-assembly is then placed into the open end of the rear housing member 92 as shown in FIG. 8 with the core ring 136 and armature assembly received within the central bore of the bobbin 127 and the spherical end 160 of the armature received within the rear core member 142. Face plate 132 will then be seating or abutting against the aforementioned circular land portion 114 of the rear housing member 92.

FIG. 13 illustrates another sub-assembly of the actuator unit comprising a stop plate element 170, a stop bushing 180, and a flexible impervious diaphragm 190 having a pair of centrally apertured stiffener plates 192,193 bonded to the opposite sides thereof. Stop plate 170, which is of zinc die-cast construction, is shown in FIG. 10 as having a peripheral axially extending rim portion 171, a reinforced radially extending web portion 172 and a centrally located hub portion 173. I-lub portion 173 has a bore 174 extending therethrough with a shallow counterbore 175 formed from one side thereof opposite the side thereof adjacent the diaphragm. In the rearwardly disposed faced 176 of the rimmed portion of the stop plate is a circularly extending shallow groove 178 which communicates with a plurality of equally angularly spaced slots 179 forming drain or vent passages extending radially inwardly of the rimmed portion of the stop plate. The groove 179 also communicates with the notches 134 in the face plate 132 registering with the vents 115 in the housing 92 to vent the interior of the housing structure.

Bushing 180 shown in enlarged detail in FIG. 11 is of stepped cylindrical formation having a reduced section 181 and an enlarged section 182 with a radially outwardly extending flange 183, formed on its enlarged section and a radially inwardly extending flange 184 on its reduced section. Section 182 of the bushing is of slightly lesser diameter than the bore 174 in the stop plate 170 and its flanged end 183 is of greater diameter than the bore so as to limit against the face of the stop plate and be received within the counterbore 175 therein as shown in FIG. 12.

The diaphragm and stiffener plate assembly are then then inserted on the reduced end of the bushing as shown in FIG. 13 with the back stiffener plate 193 abutting against the shoulder 185 formed between the reduced and enlarged sections 181 and 182 of the bushing and are staked to the reduced end thereof as shown. The stop bushing 180 and diaphragm 190 thus are retained on the stop plate 170 as a loose, floppy sub-assembly and are axially movable relative thereto by an amount corresponding to the axial length 1 of the enlarged section 182 of the bushing between the shoulder 185 and the radially outwardly extending flange 183 thereof plus the depth or axial extent of the stop plate counterbore 175 less the axial thickness of the hub portion 173 of the stop plate all of which dimensions are accurately controlled. The stop bushing is thus movable between the above noted stop limits, which define the range of travel or control of the vacuum section of the actuator unit and forms, with the control link 102, a part of the yieldable or telescoping thrust rod assembly 101, as later described.

The control link element 102, which has not yet been attached to the distributor breaker plate 50, is inserted into the axial bore of the housing member 92 and through the tubular core member 142, armature assembly 150 and core ring 132 of the solenoid structure. As shown in FIG. 14, it is positioned or displaced sufficiently forwardly in the housing member 92 to place an E-shaped retainer ring 104 on a grooved annular portion 105 (FIG. 3) of the cylindrical inner end of the link. A small coil spring 106 is then slipped over the inner end of the link projecting through the core ring 136 with one end of the spring abutting against the retainer ring 104 on rod 102.

As shown in FIG. 15, the aforementioned stop plate, bushing and diaphragm sub-assembly of FIG. 13 is then placed in the structure of FIG. 14 with the control link 102 passing through the forward end of the stop bushing 180, thereby capturing the other end of the spring 106 against the inner surface of the radially inwardly extending flanged end 184 of the bushing. A circular push-on retaining ring 107 shown in FIG. 2 is then inserted over the projecting end of the control link and is positioned against the outer surface of the forwardly located flanged end 184 thereof.

The rear housing member 92 with the components thus far described and assembled therein is then placed in a hydraulic press having three coaxial telescoping circular ram sections. The rams are brought to bear respectively on the rim portion of the stop plate 170, on the front stiffener plate 192 of the diaphragm assembly, and on the retaining ring 107 on the control link 102.

This positively seats and positions the stop plate against the stationary face plate 132 and land portion 114 of the rear housing member, the diaphragm assembly against the forwardly located side of the stop plate 170, and the retaining ring 107 against the forward end of the bushing 180.

As shown in FIG. 16, the remaining components of the actuator unit, including a headed cap screw 200 and a longitudinally movable threaded nut 206, are received within the hexagonally-shaped forward portion 118 of the housing member 91 that cooperates with a hexagonally shaped enlarged head or flange 207 on nut 206. Nut 206 is thus constrained against relative rotative movement on the adjusting screw 200 by the complementary hexagonal shape of the forward end portion 118 of the housing member 91. A coil spring 210 is then placed against the inner surface of the head 207 of the nut 206, and a compressible, rubber annular sealing washer 220 and a cup-shaped sealing cap 222, having a radially outwardly extending flanged brim 224 thereon, are then placed on the front stiffener plate 192 of the diaphragm assembly.

Housing member 91 with the aforementioned elements 200,206 and 210 therein is then placed with its flanged portion 121 against the forward face of the rim portion 172 of the stop plate and the other end of the spring 210 against the flanged brim 224 of the sealing cap 222. Then the forward end of the cylindrical portion 113 of the rear housing member 92 is curled over against the flange 121 to clamp the diaphragm about its periphery between the rimmed portion of the stop plate and housing assembly, thereby completing the actuator structure.

As shown in FIG. 16, the head 201 of the adjusting screw 200 includes several equally spaced radially extending grooves as 202 communicating with the interior of the spout 119 and the vacuum chamber for exposing the vacuum section of the actuator unit to a suitable source of suction. A hexagonally shaped socket 203 is provided in the head and body portion of the adjusting screw 200 for reception of an adjusting tool as an allen wrench 208 therein for adjusting the spring bias of the calibration coil spring 210. Spring 210 sets the vacuum pressure threshold level that the applied vacuum must overcome to compress the spring and permit displacement of the diaphragm.

The resulting structure with the outer end of the control link 102 projecting from the rear housing member 92 is then placed in a locating and drilling fixture which locates the proper position of the aperture 108 for the hinge pin 109, with reference to the correct positioning of the breaker plate 50 in the distributor. The hinge pin is then secured in the flattened offset outer end of the control link, which rides on the base plate 21, and is pivotally coupled to the breaker plate 50. The actuator unit is then mounted by its bracket 92and fastened to the distributor housing by the attachment screws 94, after which the distributor and actuator unit are placed in a distributor calibrating stand for setting the threshold vacuum level of the vacuum section by adjustment of the adjusting screw 200 as previously described.

The distributor with the calibrated actuator unit attached thereto is then mounted in an engine (not shown) with the spout 119 of the vacuum section of the actuator control unit attached through a flexible rubber tube (not shown) to the carburetor spark advance port as shown in US. Pat. No. 3,561,410 for example. The

electrical pigtail 128 of the solenoid coil is connected over an electrical conductor 230 to the vehicle storage battery 232 through the key-operated vehicle ignition switch shown at 234 in FIG. 17.

In FIG. 17, the ignition switch 234 is shown in symbolic or electrical schematic form as a double pole, multiple position switch operable between a plurality of contact positions, including an Off, Run and Start position. The start contact is a momentary contact position from which the switch is returned to the Run position upon release of the ignition key by the operator upon completion of the cranking of the engine. Conductor 230 connects the actuator solenoid coil 124 to the start contact associated with the depicted lower pole 236 of the ignition switch that is also conencted to the starting relay 238 for the engine starting solenoid (not shown).

The normal or initial position ofthe parts of the actuator unit are as shown in FIG. 3, in which the armature element 156 is spaced from the flanged end 140 of the core ring 136 by the distance A defining the solenoid air gap. Upon energization of the coil 124, the solenoid will create a magnetic field, which will be of an annular torroidal shape and extends through the armature member 156, the rear tubular core member 142, the cup-shaped portion 110 of the rear housing member 92, the face plate 132 and the inner core ring 136, all of which are formed of high permeability, low carbon steel. The control link 102 is formed preferably of nonmagnetic material, such as aluminum, so as to be uninfluenced by the magnetic field of the solenoid coil. Upon energization of the coil, the armature element 156 is attracted to the end face 140 of the core ring 136 to move the armature carrier 152 in a spark advance direction from the positive stop position shown in FIG. 3 to the position shown in FIG. 2 and close the air gap. The E-shaped retainer ring 104 on the control link 102 is located in the direct path of and against the armature carrier 152, and therefore is displaced by the amount of the controlled air gap to set the actuator link in an advanced starting position for starting. Since the coil spring 106 is of a lesser spring rate than the diaphragm spring 210, it is compressed with the forward movement of the link 102 to displace the timing link 102 from or relative to the forward end of the housing 180 which is held against the forward face of the stop plate 170 by the diaphragm spring 210. It will be noted that the inner surface 139 (FIG. 2) of the inwardly extending flange 138 of the core ring 136 forms the initial stop position of the link, while the opposite side or face 140 of the flange portion 138 forms the positive stop position to which the link is displaced by the solenoid section of the actuator unit.

After the engine is started and the ignition switch is returned to the engine run position, the solenoid coil 124 is deenergized and the timing link 102 is restored by the smaller spring 106 to the position shown in FIG. 3 with the armature carrier 152 positioned against inner face 139 of the inwardly extending flange 138 of the core ring 136. In this initial position of the timing link and timing plate, the engine timing is set in the spark retarded position for reduced exhaust emissions.

As the vacuum in the vacuum chamber formed between the capped diaphragm assembly and the inner surface of the forward housing member 91 is increased, the diaphragm spring 210 is compressed to permit displacement of the capped diaphragm assembly under the engine suction. As the diaphragm is displaced, it

carries the bushing 180 secured thereto. The forward end of the bushing abuts against and picks up the pushon retainer ring 107 on the timing link 102 to carry the timing link therewith. Thus, the timing link is moved from the position shown in FIG. 3 until the outwardly extending flange 183 on the bushing is received in the counter bored portion of the stop plate which defines the maximum forward advance position of the timing link and timing plate and the positive stop position to which the link is displaced by the vacuum section of the actuator unit.

What is claimed is:

l. The combination with an emissions controlled internal combustion engine operable at idle and off-idle conditions and producing a source of variable engine suction, of an ignition distributor having adjustable spark timing control means therein including an adjustable timing plate initially set when the engine is off in a position corresponding to a desired spark retarded position for reduction of vehicle exhaust emissions at engine idle conditions, engine starting means including a source of electrical energy and an ignition switch operable between several positions including a start position and a run position, and actuator apparatus coupled to said adjustable timing plate of said spark timing control means and operable from said electrical source when said ignition switch is in its start position for adjustment of said spark timing control means at engine starting in a spark advance direction from its initially set spark retarded position and operable thereafter from said source of engine suction during engine run conditions for independent adjustment of said spark timing control means also in a spark advance direction from its said initially spark retarded position at which it is set for both engine off and engine idle conditions and from which it is advanced during both engine starting and off-idle run conditions.

2. The combination in accordance with claim 1 wherein said actuator apparatus provides a fixed predetermined amount of spark advnace adjustment of said spark timing control means during engine starting and a continuously variable amount of spark advance adjustment thereof in accordance with prevailing engine suction during off-idle runconditions.

3. The combination in accordance with claim 2 wherein the spark advance adjustment provided by said actuator apparatus during off-idle run conditions is varied over a predetermined range of spark advance settings which includes said fixed amount of spark advance adjustment.

4. The combination in accordance with claim I wherein said actuator apparatus includes electrically operated motor means energizable from said electrical source through said ignition switch when the switch is in its start position, vacuum operated motor means connected to said engine suction source, and means coupling both said motor means to said adjustable spark timing control means for independent selective actuation thereof.

5. The combination in accordance with claim 4 wherein said coupling means decouples said electrical motor means from movement with said adjustable spark timing control means by said vacuum motor means.

6. The combination in accordance with claim 4 wherein sadid spark timing control means includes an elongated timing link coupled to the timing plate and extending externally of the distributor and wherein said electrical motor means and said vacuum motor means are spaced apart in the direction of extent of said timing link externally of the distributor and wherein said timing link has a pair of motor movement pickup abutments fixed thereto and spaced apart in the direction of extent thereof and respectively located in the path of actuation movement of said motor means.

7. The combination in accordance with claim 6 above wherein the pickup abutment for said electrical motor means is located between said electrical motor means and said vacuum motor means.

8. The combination in accordance with claim 7 wherein said vacuum motor means and said electrical motor means are contained within the same housing and said electrical motor means comprises a stationary solenoid coil and an armature of tubular form movable within said solenoid coil and surrounding said timing link.

9. The combination in accordance with claim 8 wherein said timing link passes centrally through said armature and is composed of non-magnetic material.

10. The combination in accordance with claim 9 wherein said electrical motor means further includes a first annular core portion at one end of said solenoid coil and a second tubular core portion at the other end of said coil and wherein said armature is movable between said core portions.

11. A combination vacuum and solenoid operated actuator unit for an engine ignition distributor equipped with means for adjusting the engine timing including an adjustable timing plate, said actuator unit comprising a housing, diaphragm means forming a displaceable wall of a suction chamber defined in a portion of said housing and adapted to be connected to a source of engine vacuum, stop means external to said chamber, means biasing said diaphragm means against one side of said stop means, a solenoid located externally of said chamber and including an electrically energizable solenoid coil, a stationary core portion and an armature movable in the direction of engine suction displacement of said diaphragm means from an initial stop position spaced from said core portion to a second stop position against said core portion upon electrical energization of said coil, and a yieldable thrust rod assembly including a first member secured to said diaphragm means for movement therewith, a second member extending through said housing and pivotally coupled to said timing plate, and yieldable means extending between said first and second members permitting displacement of said second member relative to said first member upon energization of said solenoid, said first member having a portion thereon spaced from and cooperating with the other side of said stop means to limit thereagainst in the course of displacement of said diaphragm means from its initial position against the said one side of said stop means, said second member coupled to said first member and to said armature for selective independent movement in the same direction from engine vacuum actuated displacement of said diaphragm means and from solenoid actuated displacement of said armature respectively between the positive stop positions of said diaphragm means and the stop positions of said armature.

12. The method of operating an emissions controlled internal combustion engine having an electrical starting motor switch and an adjustable spark timing control therein of which the latter is initially set, when the engine is off, in a position corresponding to a desired spark retarded position for reduction of vehicle exhaust emissions at engine idle, which method comprises the steps of:

electrically advancing the spark timing control a predetermined amount from its initially set position in direct response to actuation of said starting motor switch,

restoring the spark timing control to its initially set spark retarded position after the engine has started, and thereafter advancing the spark timing control from its initially set spark retarded position in accordance with indicia of engine operation for advancing said timing. 

1. The combination with an emissions controlled internal combustion engine operable at idle and off-idle conditions and producing a source of variable engine suction, of an ignition distributor having adjustable spark timing control means therein including an adjustable timing plate initially set when the engine is off in a position corresponding to a desired spark retarded position for reduction of vehicle exhaust emissions at engine idle conditions, engine starting means including a source of electrical energy and an ignition switch operable between several positions including a start position and a run position, and actuator apparatus coupled to said adjustable timing plate of said spark timing control means and operable from said electrical source when said ignition switch is in its start position for adjustment of said spark timing control means at engine starting in a spark advance direction from its initially set spark retarded position and operable thereafter from said source of engine suction during engine run conditions for independent adjustment of said spark timing control means also in a spark advance direction from its said initially spark retarded position at which it is set for both engine off and engine idle conditions and from which it is advanced during both engine starting and off-idle run conditions.
 2. The combination in accordance with claim 1 wherein said actuator apparatus provides a fixed predetermined amount of spark advnace adjustment of said spark timing control means during engine starting and a continuously variable amount of spark advance adjustment thereof in accordance with prevailing engine suction during off-idle run conditions.
 3. The combination in accordance with claim 2 wherein the spark advance adjustment provided by said actuator apparatus during off-idle run conditions is varied over a predetermined range of spark advance settings which includes said fixed amount of spark advance adjustment.
 4. The combination in accordance with claim 1 wherein said actuator apparatUs includes electrically operated motor means energizable from said electrical source through said ignition switch when the switch is in its start position, vacuum operated motor means connected to said engine suction source, and means coupling both said motor means to said adjustable spark timing control means for independent selective actuation thereof.
 5. The combination in accordance with claim 4 wherein said coupling means decouples said electrical motor means from movement with said adjustable spark timing control means by said vacuum motor means.
 6. The combination in accordance with claim 4 wherein sadid spark timing control means includes an elongated timing link coupled to the timing plate and extending externally of the distributor and wherein said electrical motor means and said vacuum motor means are spaced apart in the direction of extent of said timing link externally of the distributor and wherein said timing link has a pair of motor movement pickup abutments fixed thereto and spaced apart in the direction of extent thereof and respectively located in the path of actuation movement of said motor means.
 7. The combination in accordance with claim 6 above wherein the pickup abutment for said electrical motor means is located between said electrical motor means and said vacuum motor means.
 8. The combination in accordance with claim 7 wherein said vacuum motor means and said electrical motor means are contained within the same housing and said electrical motor means comprises a stationary solenoid coil and an armature of tubular form movable within said solenoid coil and surrounding said timing link.
 9. The combination in accordance with claim 8 wherein said timing link passes centrally through said armature and is composed of non-magnetic material.
 10. The combination in accordance with claim 9 wherein said electrical motor means further includes a first annular core portion at one end of said solenoid coil and a second tubular core portion at the other end of said coil and wherein said armature is movable between said core portions.
 11. A combination vacuum and solenoid operated actuator unit for an engine ignition distributor equipped with means for adjusting the engine timing including an adjustable timing plate, said actuator unit comprising a housing, diaphragm means forming a displaceable wall of a suction chamber defined in a portion of said housing and adapted to be connected to a source of engine vacuum, stop means external to said chamber, means biasing said diaphragm means against one side of said stop means, a solenoid located externally of said chamber and including an electrically energizable solenoid coil, a stationary core portion and an armature movable in the direction of engine suction displacement of said diaphragm means from an initial stop position spaced from said core portion to a second stop position against said core portion upon electrical energization of said coil, and a yieldable thrust rod assembly including a first member secured to said diaphragm means for movement therewith, a second member extending through said housing and pivotally coupled to said timing plate, and yieldable means extending between said first and second members permitting displacement of said second member relative to said first member upon energization of said solenoid, said first member having a portion thereon spaced from and cooperating with the other side of said stop means to limit thereagainst in the course of displacement of said diaphragm means from its initial position against the said one side of said stop means, said second member coupled to said first member and to said armature for selective independent movement in the same direction from engine vacuum actuated displacement of said diaphragm means and from solenoid actuated displacement of said armature respectively between the positive stop positions of said diaphragm means and the stop positions of said armature.
 12. The method of operating an emissions controlled interNal combustion engine having an electrical starting motor switch and an adjustable spark timing control therein of which the latter is initially set, when the engine is off, in a position corresponding to a desired spark retarded position for reduction of vehicle exhaust emissions at engine idle, which method comprises the steps of: electrically advancing the spark timing control a predetermined amount from its initially set position in direct response to actuation of said starting motor switch, restoring the spark timing control to its initially set spark retarded position after the engine has started, and thereafter advancing the spark timing control from its initially set spark retarded position in accordance with indicia of engine operation for advancing said timing. 